The best time for stocking pools is in late spring and early summer. Some of the plants require soil in which tobut some are free-floating in the water.
There are two ways of providing soil for those plants that require it; one is to spread soil on the bottom of the pool, either all over or in low mounds here and there, the other is to put the soil inor baskets, plant the aquatics in these, and then stand them in the pool, weighting them if necessary to keep them steady. This latter method has considerable advantages in small pools as it makes it much easier to lift the plants out when they require attention or the pool needs cleaning.
Either way, ordinary garden soil can be used but good quality rather stiff loam is better. A small quantity of bonemeal (about 8 oz, 225 g. per bushel) can be added to the loam but other fertilizers are best kept out of the pool and so is animal manure.
The Ideal Way The ideal way to stock a new pool is to put the soil and rooting plants inand then carefully run in enough water to cover them to a depth of an inch or so. Then, as they start to grow, more water can be added a little at a time until, after three or four weeks, the pool is completely filled. Of course this method will not work if shelves have been made for marginal plants, unless the plants are in boxes or baskets and can be stood in the bottom of the pool to begin with, those intended for the margins being lifted to the shelves later. An alternative to this method if it is more convenient to fill the pool straight away, or when adding new plants to pools already stocked, is to plant in or baskets and stand these on bricks to bring them quite close to the surface, later removing the bricks one at a time as the plants grow and require a greater depth of water over them.
Free-floating plants can simply be dropped into the water, perhaps with a small stone tied to the lower end of each to act .as an anchor. This should be done when the pool is reasonably well filled with water.
Introducing Fish to the Pool
Fish can come in a little later when the plants, both soil-rooting and free-floating, are beginning to get established and provide that shelter which fish must have if they are to thrive. Some of the free-floating plants perform a useful function in supplying oxygen to the water which helps to keep it fresh and in good condition for both plants and fish. Do not overstock pools with either plants or fish. It is impossible to be dogmatic about this but a fair average is not to exceed 4 in (10cm) of body length, excluding tail, per square foot (30cm sq) of surface area of water.
Crystal clear water is only possible where it is chemically treated or is constantly being changed. Chemical treatment makes it impossible to grow plants or stock with fish. Though it is possible to grow some plants and to have some fish in water that is moving slowly, as a rule in the garden one must be satisfied with the same water most of the time and that, in turn, means that it cannot be completely clear. The amount of discoloration, weed and scum will, however, depend to some extent on the way in which the pool is stocked. At first there is likely to be a good deal of discoloration, but as plants settle in, the free-floating plants produce their full quota of oxygen, and the fish begin to, a balance should be struck and the water should begin to clear.
In summer green scum and the greeny yellow cotton-wool-like growth known as blanket weed may make their appearance. They are natural weeds of still water and, like other weeds, must be removed. This can be done by careful raking or by drawing a sack or a sieve through the water.
Cleaning and Re-stocking a Pool
It should not be necessary to clear a pool every year, but small pools do get overcrowded fairly easily so, every second or third year, preferably in late spring, the pool should be emptied, plants and fish removed to buckets or tubs, the pool itself scrubbed out and then re-stocked. This is the opportunity to divide the plants, throwing away or giving away what is not required and replanting only sufficient to give the pool its correct balance of plants and fish. Do not use chemicals or detergents when cleaning out the pool – just plenty of clean water.
Recommended Aquatic and Waterside Plants
Acorus (Sweet flag) Fragrant, sword-like, margined with pink, yellow and white in the variety Acorus calamus varie-gatus. It likes to grow in wet soil or up to 4 in (10cm) of water.
Alisma (Water plantain) A plant for the margin of a pool in 2 or 3 in (5 to 8 cm) o\’ water. Alisma plantago-aquatica has broad, erect leaves and small pink and whitein 2-ft (60-cm) high branching sprays in summer.
Aponogeton (Water hawthorn) The oval leaves of Aponogeton distachyus float on the surface like those of aand the need to grow in soil not more than 18 in (45cm) below the surface. It will grow in as little as 4 in (10cm) of water. The small white are carried in short spikes in late spring and early autumn and are sweetly scented.
Arrowhead, see Sagittaria
Bog arum, sec Calla
Bog bean, see Menyanthes
Brandy bottle, see Nuphar
Bulrush, see Scirpus
Butomus (Flowering rush) Only one kind is grown, Butomus umbellatus, a plant with narrow reed-like leaves and stout 3-ft (1 -m)bearing, in late summer, clusters of soft pink flowers. It likes to grow in water 3 or 4 in (8 to 10 cm) deep.
Calla (Bog arum) Calla palustris is a miniature relative of the familiar arum lily with little yellow and green flowers on 6-in (15-cm)in early summer. It is a plant for the extreme margin of the pool in water no more than 2 in (5 cm) deep.
Caltha (Marsh marigold, kingcup) This is the much-admired plant of damp meadows and streamsides in Britain, with shining green leaves and large, golden-yellow buttercup-like flowers in spring. The common kind is Caltha palustris and there is a showy variety with double flowers named f/ore-pleno. Yet another kind with extra large single flowers is C. polypetata. All like to grow in damp soil right at the edge of a pool or stream rather than in the water.
(Umbrella grass) Rushy plants with brownish flowers borne on short stems surmounted by narrow leaves or bracts arranged like the spokes of an umbrella. Cyperus vegetus is 2 ft (60 cm) high. C. longus, 3 to 4 ft (1 to 125 m). Both grow well in wet soil at the edge of a pool but themselves about rather too freely.
Elodea Two useful submerged aquatics to supply oxygen to the water and provide shelter for fish are Elodea canadensis and E. crispa, but both grow rapidly and may have to be thinned out from time to time. In some catalogues these plants may be listed as anacharis.
Flowering rush, see Butomus
Golden club, see Orontium
Hottonia (Water violet) Hotionia palustris is a submerged plant with ferny leaves and sprays of pale lavender flowers a few inches above water level. This is a good oxygenating plant.
Several kinds of iris are excellent water or waterside plants. Iris laevigata is 2 ft (60cm) high and has broad-petalled flowers in white or various shades of blue, purple and pink. It thrives in 2 to 4in (5 to 10cm) depth of water as does the tall yellow Hag. /. pseudacorus with larger flowers. /. sibirica, with narrow grassy leaves and elegantly formed flowers on 24-ft (75-cm) stems, and /. kaempferi, similar in height but with much larger, broader-petalled tlowers in a range of colour from white to deep purple. Like the damp soil near pools or streams but should not be covered with water.
Juncus (Rush) There are a great many kinds of rush, one of the best for the garden pool being Juncus effusus spiralis, known as the corkscrew rush because its 18-ih (45-cm) high stems are twisted like a corkscrew. It will thrive in damp soil or in 2 or 3 in (5 to 8 cm) depth of water.
Kingcup, see Caltha
Lysichitum (Skunk cabbage) Plants with arum-like flowers in spring followed by large, over-profuse leaves. Lysichitum ameri-canum, the kind commonly planted, has large yellow flowers: L. camtschatcense, has smaller white flowers. Both can be grown in wet soil near a pool or stream or in 2 or 3 in (5 to 8 cm) depth of water.
Marsh marigold, see Caltha
Mentha (Mint) The water mint, Mentha aquatica, has mint-scented leaves and heads of small mauve flowers in summer. It likes the damp soil at the edge of a pool.
Menyanthes (Bog bean) Menyanthes trifoliate is a native plant which thrives in shallow pools, pushing up three-parted leaves above the surface and, in midsummer, clusters of white or pinkish flowers. It likes wet soil or up to 4in (10cm) of water.
(Musk, monkey flower) The yellow musk, luteus, is an excellent plant for damp soil or an inch or so of water. It carries its deep yellow flowers on 9-in (23-cm) stems all summer and there are varieties with spotted flowers. M. ringens is 18 in (45 cm) high and has flowers of a lavender colour.
Mint, see Mentha
Monkey flower, see Mimulus
Musk, see Mimulus
Myosotis (Water forget-me-nol) Myosotis palustris is like a paler blue version of the common forget-me-not and it thrives in the damp soil at the edge of a pool.
Myriophyllum Several kinds are grown to supply oxygen to the water and provide shelter for fish. All are completely submerged and have fern-like foliage.
Nuphar (Brandy bottle) These look likeand have similar floating leaves but the flowers are smaller, more globular and bright yellow. The kind commonly grown is Nuphar luteum, a British wild plant which is vigorous and spreads rapidly. It will grow in up to 2 ft (60cm) of water and. Unlike water lilies, will open its flowers in shade.
Nymphaea( Water lily) Although they appear to float on the surface of pools, water lilies in fact, like any terrestrial plant, into soil. There should either be a depth of several inches of good loamy soil in the bottom of the pool or each water lily should be planted in a basket or box filled with soil and sunk in the pool. Most water lilies thrive best in water 12 to 18 in (30 to 45cm) deep. A few, such as the white water lily, Nymphaea alba, like water 2 to 3 ft (60cm to 1 m) deep. By contrast, the pygmy water lily. A’, tetragona, does not need more than 5in (13cm) of water and will grow with even less. Some of the best garden kinds are hybrids, such as James Brydon, red; Escarboucle. Crimson, and Arey, pink.
All should be planted in late spring and may be increased by careful division of their fleshyat the same season. They are best left undisturbed for several years until they become overcrowded.
Nymphoides (Water fringe) The floating plant often called Villarsia nymphaeoides in catalogues should really be Nymphoides peltatum. The leaves are rather like those of a water lily on a reduced scale and the clusters of bright yellow, poppy-like flowers have fringed petals. It likes to grow in 12 to 18 in (30 to 45 cm) depth of water.
Orontium (Golden club) The rather stiff shining leaves of Orontium aauaticum float on the surface and the flowers are small. Yellow and closely clustered on a slender heart-shaped leaves and 2-ft (60-cm) spikes of light blue flowers in summer.
Reed mace, see Typha
Rush, see J uncus
Sagittaria (Arrowhead) Marginal plants with upstanding arrow-shaped leaves and stiff sprays of white flowers in summer. Sagittaria sagittifolia is a native plant 2 ft (60cm) high which has an even better double-flowered variety sometimes called ftore-pleno and sometimes japonica. It likes 3 or 4 in (8 to 10cm) depth of water.
Scirpus (Bulrush) This is not to be confused with typha, a plant with cigar-like flower spikes often incorrectly known as bulrush. Scirpus has rushy leaves and rather insignificant clusters of flowers. The best variety for the garden. Scirpus tabernaenumtani zebrinus, has leaves shaped rather like porcupine quills, banded with green and white. It grows very well in 3 or 4in (8 to 10cm) of water.
Skunk cabbase. See Lysichitum
Sweet Hag, see Acorns
Typha (Reed mace) The plants many people wrongly call bulrushes. The common reed mace, Typha latifolia, is a native plant 6 ft (2 in) high with large cigar-like flower heads in late summer. Better for the garden pool are T. angustifolia, with narrower leaves and flower heads on 4-ft (1-25-111) stems, and T. minima, only 18 in (45cm) high. Ail thrive in 3 or 4 in (8 to 10cm) depth of water.
Umbrella grass, see Cyperus
Villarsia, see Nymphoides
Water forget-me-not, see Myosotis
Water fringe, see Nymphoides
Water hawthorn, see Aponogeton
Water lily, see Nymphaea
Water plantain, see Alisma
Water violet, see Hottonia
Zantedeschia (Arum lily) The familiar arum lily of florists” shops with its gleaming white spathes, each with a central golden column or spadix, is usually grown in greenhouses but it is sufficiently hardy to be grown outdoors in the mildest parts of the country. Elsewhere it can be put out all summer and brought into protection in the autumn. It grows well in the damp soil around pools and may even spread into the shallow water.